FR2785580A1 - METHOD FOR MANUFACTURING A SEAT BODY WITH A CONCAVE USEFUL SURFACE - Google Patents

Abstract

The invention relates to a method for manufacturing a seat body with a concave useful surface, comprising a molded body with a concave surface and a seat covering said surface. According to the invention, a covering cutout (5) is placed on a convex perforated sheet (10) whose shape corresponds to the concave surface (3) of the molded body, then is shaped on this perforated sheet under the effect of 'a depression, the areas of the overlapping cutout (5) adjacent to the convex perforated sheet (10) below the highest geodesic point being pushed back in the direction of their surface; an intermediate layer (6) is placed and glued on the covering cutout (5); an upper molded part (25) is hot pressed on the intermediate layer (6), in order to harden the covering cutout (5) with the intermediate layer (6) to form a seat; the seat obtained is finally placed on the concave surface of the molded body and fixed by its edge to the edge of the concave surface of the molded body.

Description

The invention relates to a method of manufacturing a seat body with

  concave working surface, comprising a molded body with a concave surface and a facing seat with overlapping cutout covering this concave surface5. By seat body is meant both the backrests and the seat elements themselves. Such seat bodies are used for furniture, for user seats in public transport or for

  passenger seats in vehicles.

  In particular in vehicles, a shape matching that of the body and lateral support in turns require the configuration of concave surfaces for both the back and the seat. In practice, it is known to manufacture, as a seat, a covering cutout laminated to a foam, and as a general rule also compression molded in order to then bond it to this molded body. However, during compression molding of the covering cutout, there are either folds or tensile forces, or both. The folds are not aesthetic, are unpleasant for the seated person, and are therefore not accepted by

  the buyer. Tensile forces induce stresses

  your own which lead to the detachment of the bonding during the lifetime. The seat then loses its concave shape and remains free on the molded body which makes

messy and not pleasant.

  The bonding of the seat to the molded body is also disadvantageous since it makes it difficult to

  housing - generally optional - of heating spirals

  seat or seat sensors and that it causes

  all in all, subjectively uncomfortable seating comfort

  gréable. The objective of the invention is therefore to propose a method which avoids these drawbacks and which allows the

  manufacture of seat bodies with a lasting aesthetic form

  and pleasant, with rudimentary manufacturing means

  shut up. This is obtained by a process comprising the following steps: a) a cover cutout is placed on a perforated sheet, the shape of which corresponds to that of the concave surface of the molded body, so that its outer face is oriented towards the sheet perforated; b) by the effect of a depression on the face of the perforated sheet opposite to the cover cut, the cover cut is completely shaped on the perforated sheet, the areas of the cover cut adjacent to the convex perforated sheet below the highest geodesic point thereof being driven back in the direction of their surface; c) an intermediate layer is placed on the cover cutout, the contact surfaces between the cover cutout and the intermediate layer being glued to one another; d) an upper molded part, the shape of which corresponds to the concave surface of the molded body, is hot pressed on the intermediate layer in order to harden the covering cutout with the intermediate layer to obtain a seat; e) the seat thus obtained is placed on the concave surface of the molded body and fixed by its edge to the

  edge of the concave surface of the molded body.

  The depression therefore acts through the perfo-

  ree constituting a lower mold half on the cover cutout. This is initially, apart from the influence of the forces of gravity, flat and without constraints. The attracting effect of depression increases strongly by reducing the distance

  between the perforated plate and the cover cutout.

  The latter is then gradually drawn from the highest geodesic point of the perforated sheet down. Thanks to this progressive attraction, the vacuumed area of the cover cutout can no longer move on the perforated sheet. However, it does not tend to form folds because it is slightly contracted in the direction of its surface. This avoids remaining tensile forces

  in the seat in the form of own constraints and for-

  could loosen the collage after a while.

  The bonded intermediate layer has the effect that after hardening by the displacement of the surface of the intermediate layer, during positioning on the already shaped covering cut-out and by the opening of the foam cells on the contact surface, the seat

  retains its shape throughout its lifetime and does not require

  site therefore not to be glued on the molded body. However, this facilitates the replacement of the seat body and the mounting and replacement of heated seat coils or seat sensors, and also improves comfort.

subjective seating.

  In a development of the process according to the invention

  tion is placed, during the shaping of the overlap cutout

  gently on the perforated sheet (step b), a sliding frame on the cover cutout which descends with the edge of the cover cutout on the perforated sheet. In the case of a more rigid cover cutout, the sliding frame considerably facilitates conforming without creases on the perforated plate. Since this frame is only an aid - the main work done by the depression - it does not require its own drive, it descends by its own weight, the slippery cover cutout

slightly below.

  For its shaping it is not necessary that the covering cutout is permeable, to gases, the depression producing its effect without that. It is therefore also possible to use closed textiles, imitation leather or even real leather. If the covering cut is made of a conventional gas-permeable textile, a development of the invention provides that the intermediate layer also can be shaped using the depression on the already shaped covering cut. In a preferred embodiment, the covering cutout is a textile, constituting the outer face, laminated on a layer of foam with a thickness of between 1 and 6 minutes, preferably about 3 minutes, and the intermediate layer is in foam with a thickness of between 3 and 20 minutes, preferably between 4 and 7 minutes. These proportions have been found to be particularly advantageous for shaping without wrinkles and for

seating comfort.

  In an advantageous development of the process, the upper molded part is also configured as a perforated sheet and the heat necessary for hardening is brought by blowing a stream of hot air. So we can reduce the curing time and get a

  homogeneous hardening with few means.

  As part of the method, it is also expected that the overlapping cutout has a border beyond the intermediate layer and which will be connected to the molded body, or else sewn on other textile cutouts outside the concave surface. So we prepare and facilitate the next processing step in the

  process according to the invention without additional means.

  If we use the sliding frame for positioning the intermediate layer, we increase

  also the seat adjustment precision.

  Finally, given that thanks to the perforated sheet, the method according to the invention does not require significant depression, this can be generated very

  economical with a simple fan.

  Hereinafter the invention will be described in more detail and explained with the aid of drawings, in which: FIG. 1 is a cross section of a seat body produced according to the method according to the invention, FIG. 2 is a diagram of the first step of the method according to the invention, FIG. 3 is a diagram of the second step of the method, FIG. 4 is a diagram of the third step of the method, FIG. 5 is a diagram of the fourth step

of the process.

  Figure 1 is a cross section of a seat body 1 which can be both a backrest and a seat element itself. In any case, it has a contour (concave, cylindrical or spherical). It comprises a molded body 2 with a concave surface 3 corresponding to the concave contour, and a seat 4 formed according to the invention by a cover cutout 5 and an intermediate layer 6. The cover cutout 54 has on both sides an edge 7 which is fixed in the molded body 2 for example using clips 8. The edges 7 can however also be sewn with adjacent textile cutouts (not shown here). The molded body 2 is by

  example of polyurethane foam which has a resistance

  sufficient crushing strength. The covering cutout 5 is for example a textile material forming the visible face, and the hidden face of which is laminated on a laminating foam with an apparent density of approximately 35 to 60 kg / m 3 and a thickness of 3 minutes. . The

  intermediate layer is for example of foam against

  bonding of an apparent density of 35 to 60 kg / m3 and a thickness of 5 min. In Figure 1 is further

  suggested a seat sensor 9 placed under the seat 4.

  For the manufacture of such a seat body according to the method according to the invention, an installation is used shown diagrammatically, as an example in FIG. 2, which, playing, so to speak, the role of half of the lower mold, has a perforated sheet 10 arranged on a work table 11 constituting an airtight box and being in communication with a suction draft fan 12 by means of valves 13. The perforated sheet 10 has a convex shape corresponding to the concave surface 3 of the molded body 2 and the entire surface of which in contact with the covering cutout 5 is provided with holes, for example with a diameter of 1.5 min and distant from each other by about the same value. It can be seen that the still flat cover cutout 5 has a length 16 with respect to the final dimension forming the edge of the cover cutout. The covering cutout 5 is placed with its outer face 15 (front) downwards on the perforated sheet 10 on which is then applied a sliding frame 14 with downward movement but without

special training.

  If the fan 12 is started and the valves 13 are opened, see FIG. 3, by creating a depression in the space 18, respective areas of the cover cutout 5 are attracted towards the perforated sheet at from the highest geodesic point 20, where the overlapping cutout is first placed, by hypsometric curves downwards, they are applied against the perforated sheet and are prevented by the depression from

  move - which would lead to tensile forces.

  They are helped for this by the sliding frame 14 which descends by its own weight, on the underside of which passes the over length 16 of the edge, which is then somewhat

  so pulled and smoothed to avoid wrinkles.

  Then, see figure 4, the contact surface 22

  between an intermediate layer 6 and the blanking cutout

  ment 5 is coated with a suitable adhesive (for example a two-component polyurethane adhesive) and this intermediate layer 6 is placed on the overlapping cutout

  5. The sliding frame 14 helps with precise positioning.

  For an airtight cover cut, the positioning can be done manually, and for an air permeable cover cut 5, the molding is carried out as previously by the depression in the space 18. For hardening, see Figure 5, of the seat 4 thus formed, an upper molded part 25 is pressed on the intermediate layer 6, which is suggested by the arrow 26. The upper molded part 25 can also be a perforated plate. Above is placed a cover 27 which by means of a recovery sheath

  air 28 is connected to a heating means 29 with the ventila-

  tor 12, so that the air stream 30 generated by the latter is returned to the cover 27 through the

heating medium 29.

  The seat 4 being compressed between the perforated sheets 10 and 25, it can be traversed by the current of hot air 30 allowing its particularly rapid and uniform hardening. During hardening, the structure and shape of the seat 4 are stabilized by the fact that, by the surface displacement of the covering cutout 5 and of the intermediate layer 6 during their positioning, a portion of the foam cells close to the contact surface 22 burst, thereby also stabilizing the adhesive layer. The product thus obtained therefore has no constraints inside and will keep its shape for a very long time. Thus, it is no longer necessary to glue it to the molded body 2. It is sufficient to fix it to the molded body 2 using the edges 7 which are not laminated, which is obtained in the embodiment shown.

  (Figure 1), using clips 8. The border 7 can however

  dant also be sewn on adjacent cuts not shown. F 1-

Claims (10)

  1. A method of manufacturing a seat body with a concave useful surface, comprising a molded body (2) with a concave surface (3) and a facing seat (4) covering this concave surface, characterized by the following steps: a ) a covering cutout (5) is placed on a perforated sheet (10), the shape of which corresponds to that of the concave surface (3) of the molded body (2), so that its outer face (15) is oriented towards the perforated sheet (10); b) by the effect of a depression on the face of the perforated sheet (10) opposite to the cover cutout (5), the latter (5) is completely shaped on the perforated sheet, the areas of the cutout covering (5) adjacent to the convex perforated sheet (10) situated below the highest geodesic point (20) thereof being pushed back in the direction of their surface; c) an intermediate layer (6) is placed on the covering cutout (5), the contact surfaces (22)   between the cover cutout (5) and the intermediate layer   diary (6) being glued to each other; d) an upper molded part (25), the shape of which corresponds to the upper surface (25), the shape of which is hot pressed on the intermediate layer (6) in order to harden the covering cutout (5) with the intermediate layer (6) to obtain a seat (4); e) the seat (4) thus obtained is placed on the concave surface (3) of the molded body (2) and fixed by its edge (7) to the edge of the concave surface (3) of the molded body. 2. Method according to claim 1, characterized in that one places, during the shaping of the covering cutout (5) on the perforated sheet (10) (step b), a sliding frame (14) on the cutout cover (5), which descends with the edge (16) of the cover cutout (5) on the perforated sheet (10).   3. Method according to claim 1, characterized in that the intermediate layer (6) is also shaped on the cover cutout (5) using a vacuum. 4. Method according to claim 1, characterized in that the covering cutout (5) is a textile, constituting the outer face (15), laminated on a layer of foam with a thickness between 1 and 6 min, preferably about 3 minutes.   5. Method according to claim 1, characterized in that the intermediate layer (6) is made of foam with a thickness of between 3 and 20 min, preferably between 4 and 7 mins.   6. Method according to claim 1, characterized in that the upper molded part (25) is also configured as a perforated sheet and that the heat necessary for hardening is brought by blowing a stream of hot air (30).   7. Method according to claim 1, characterized in that the covering cutout (5) has an edge (7) projecting from the intermediate layer (6) and which is connected to the molded body (2) outside the surface concave (3).   8. Method according to claim 1, characterized in that the covering cutout (5) has an edge (7) projecting from the intermediate layer (6) and which is sewn on other textile cutouts outside of the concave surface (3).   9. Method according to claim 2, characterized in that the sliding frame (14) is used for the   positioning of the intermediate layer (6).   10. Method according to claim 1, characterized in that the vacuum is generated by a fan (12) placed under the perforated sheet.